#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
class Solution {
public:
	int romanToInt(string s) {

	}
};
int main() {
	std::to_string()
	std::basic_string<char, std::char_traits<char>, std::allocator<char>>::append();
	Solution s;
	vector<int> a = { 2,6,4,1 };
}